1. Field
Apparatuses and methods consistent with exemplary embodiments relate to a backlight unit (BLU) and a display apparatus, and more particularly, to a BLU which displays an image using backlight radiated from a light emitting module in a display and a display apparatus.
2. Description of the Related Art
A liquid crystal display (LCD) panel cannot emit light by itself. Therefore, an LCD panel needs to have a backlight unit which provides backlight to the LCD panel.
The backlight unit includes a light emitting unit which generates backlight and a light guide plate which uniformly transmits backlight radiated from the light emitting unit onto a surface of the LCD panel. The light emitting unit includes light emitting elements which are disposed in order to efficiently provide backlight to the LCD panel and a driving element which drives the light emitting elements. An appropriate number of driving elements is provided to drive the light emitting elements without any problems.
A light emitting diode (LED) which offers high luminance, a long operating lifespan, and low thermal resistance in comparison with a cold cathode fluorescent lamp (CCFL) is mainly used as a light emitting element of a BLU. The LED can adjust its luminance using driving current supplied to the LED, and improve cognition and reduce power consumption by adjusting a voltage of a power supply unit.
In particular, since the brightness of an LED is proportional to the current supplied thereto, constant current should be supplied to enable each LED to produce uniform luminance, thereby stabilizing the luminance. Accordingly, to stabilize the luminance, each LED has to produce uniform luminance.
In order for the LEDs to produce the same luminance, the rated voltage needs to be equal at each LED. However, LEDs show a deviation of the rated voltage according to various factors such as dispersion errors and temperature change. Herein, the rated voltage is a forwarding voltage which is supplied to an LED for normal operation.
Therefore, there is a need for methods to compensate a deviation of rated voltage of an LED so that LED modules of a BLU produce uniform luminance.